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4 Sheets-Sheet 2.

(N Model.)

W. GUEsTxz '0. GOURT. TREATING TAN BARK, &G.,`TO REN'DEB, THE' SAME SUITABLE FOR USE IN MANUFAUTURING PAPER.

No.. 254,958; Patented M@r.14,1882.

(No Model.) 4 4 Sheets-Sheet 3.

W. GUEST 85 O. OOURT. TREATING TAN BARK, Ao., TO RENDER THE SAME SUITABLB FOR USE 2.. 0o oo 1 A.` 1 h a M .d .w mn e Pt Aa PPy G N I R U T O A F U N A M N I 0m 5 9, 4 5 2 0. N

(No Model.) sheets-sheer 4. Y'

W. GUEST & O. GOURT.

TREATING TAN`BARK, &., TO RENDER THE SAME SUITABLE FOR USE IN MANUFAGTURING PAPER. v

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4 NV PETEHS. Phom-Lilhognphor. WnshlrvgmnV D. C.

UNITED STATi-:s`

WILLIAM GUEST, OF DEPTFORD, OOUNTY OF KEN'LAND CHARLES OF ROTHERHITHE, COUNTY OF SURREY, ENGLAND.

PATENT OFFICE.

ooURr,

TREATING TAN-BARK, dc., T RENDER THE SAME SUITABLE FOR USE IN MANUFACTURING PAPER.

SPECIFIOATION forming part of Letters Patent No. 254,958, dated March 14, 1682. Application filed January 14, 1882. (No model.) Patented in England June 18, 1881.

To all whom tt may cancer-n:

Be it known that we, WILLIAM GUEs'r, of Deptford,in the countyof Kent,and CHARLES COURT, of Rotherhithe, in the county of Surrey, England, engineers, have invented new and useful Improvements in Treating Tan or Spent Bark to Render the same Suitable for Use in the Manufacture of Paper,of which the following is a specification.

1o The objectof this inventon is to utilize What is known as titan*7 or spent bark by preparinga fiber therefrom suitable for conversion into paper.

It has been proposed from time to time to reduce all kinds of vegetable fibers to pulp or half-stuff 'for paper-makefis use; but many of the fibrous materials mentioned-as suitable for this purpose, and among them spent bark, have offered insuperahle obstacles to the pazo per-maker through the costof their conversion into half-stuffand the inferior character of paper that couldbe produced therefrom. The spent bark of the tanner contains knots or hard poitions, Which, notwithstanding` the rough grinding operation to Which the bark is subjected before use by the tanner and the subscquent steeping received in the tan-pits, retain all their hardness and consistency and yield up little or none of their tanning property.

By the process of treatment which we will now procee'd to describe We first reduce the knots to their constituent fibers and then extract therefrom the tannin or tannicacid, which becomes a valuab'e marketable product.

In Sheet I of the accompanying drawings, Figure 1 is a Sectional elevation of the crushing-inill which We einploy in preparing the spent barlt for the after treatment, and Fig. 2 is a back elevation of the same.

A A are side frames, hraced together by stayrods, and carrying bearings for three rollers, B O D, the rollers B and O being, by preference, fluted.

E is a hopper carried by the i'raming, and

45 serving to deliver the spent bark to be oper- 4 ated upon between the rollers B and O. The

roller B acts as a feed-roller, and the roller O is a crushing-roller,'it being held in contact with the roller D by means of levers F F, piv- 5o oted to the main framing and resting on the brasses of the axle of the roller O, which brasses are free to slide in vertical slots made in the side frames.

F' F' are tension-springs, Which connect the levers F with a fixed pointon theframing, and thus cause thelevers to bear down the crushingroller O upon the roller D. The pressure put on these lovers we propose to regulate by means of adjusting-nuts, (shown in the drawings.)

G-is a driVing-shaft, having its bearings in theV side frames and receiving. rotary motion through a band from any prime mover. G' G' are the fast and loose band-pulleys on this shaft, and g is a spur-pinion on the opposite end of the shaft. This pinion g gears into a spur-Wheel, b, on the axle of the roller B and serves to impait a slow rotary motion to that roller. On the end of the shaft G, near the band-pulleys, is keyed a spur-wheel, g', Which 7o gears With a Wheel, d,on the axle of the roller D. Keyed to the opposite end of the axle of the roller D is a spur-Wheel, d', of a similar pitch, and gearing into this Wheel is a Wheel,

c, of similar pitch, keyed oii the axle of the roller O.

Supposing the hopper E to be charged With the spent tan, preferably in a dry state, on rotary motion being iinparted to the mill the roller B will force the tan forward into the bite of 8o the rollers O D, the tan being guided thereto by an adjustable scraper, H, situate between the rollers B and I), and' shown detached at Fig. 3. As the material is subjected to the crushing action of these rollers the hard knots S5 Will be reduced to a fibrous state, and the crushed bark or tan will be delivered out of the machine onto an inclined board, I, whence it is collected into a suitable receptacle. The scraper H, When properly adjusted, Will serve dgo to clear the rollers B and D from any adhering tibers, and thereby maintain the efficiency ofthe mill. The edge of the scraper next the roller Bis by preference serrated, as shown in the detached views; but this is not essential. The spent bark, when reduced by the crushing pro` cessjust described, is submitted to a steeping process, With agitation, for the purpose of eX- t-racting therefrom the tannin still remaining in the bark. For this purpose We use the arrange` 1 ao ment of apparatus shown in Sheet II of the drawing's, which consists of a rotating steamf tight boiler, in which is inclosed a series of revolving blades. Fig. 4 is a longitudinal section of this apparatus. Fig. 5 is a transverse section taken in the line 1 2 of Fig.. 4, and Fig. 6 is a plan view of the same.

K is a horizontal cylindrical boiler, domeshaped at its ends, and fitted with hollow trunnions, which work in roller-bearings carried by the end frames, L. Through the trunnions of this boiler passes a hollow axle, M, on which is mounted a series of bladcs or stirrers, N, arranged helieally around the hollow aXle. One end of this axle is closed, and theopen end tits into the stuffing-box M', communicating with a steam-supply pipe, M2. The hollow axle is piereed to allow of steam issuing from it into the boiler K, and it is fitted with band-pulleys m m for imparting an axial motion thereto.

Keyed to one of the trunnions of the boiler is a spur-wheel, k, into which gears a pinion, o, keyed ou a driving-shaft, O, having its bearings on the end frames. The driving-gear we so arrange as to rotate the hollow axle and the boiler in opposite directions, the boiler making, say, twenty-five revolutions per minute, and the axle, with its beaters, running at some four times that speed.

The boiler is provided with four man-holes for admitting the material to be treated and for discharging the same. These man-holes, which are preferably oval, are arranged longitudinally of'the boiler, and are closed by loose covers,which are secured by clamping-screws that Work through bars overlying the holes, and held in place by lugs projecting from the coverseat. i

The upper side of the boiler is provided with steam-discharge cocks and the under side of the boiler with cocks for discharging the liqnor. These cocks We fit with strainers to prevent the fibers entering and clogging up the passages.

This apparatus is intended to operate upon some half a ton ofthe crushed spent tan at one time. It is discharged into the boiler through the man-holes, and about l'orty gallons of water is added thereto. In order to qnickcn the operation of extracting the tannin, we add to the contents of the boiler a saturatcd solution of caustic sodainthe proportion of five pounds of soda, cr thereabout, to each hundred-weight of the spent tan to be operated upon. We then admit steam at about thirty pounds pressure to the boiler through the peri'orations in the hollow axle and set the boiler and the beaters in motion. This we continue for about two hours, by which time the barlt-fibers Will be separated and deprived of the tannic acid contained therein. Preparatory to discharging the now prepared fibers we shut off the steam to the hollow axleM,open the steam-discharge coclts, and open also the discharge-cocks for the liquor, which, falling into suitable receivers, is then ready for the use of the tanner. \Vhen the liquor has been run offwe open the man-holes, turn the boiler to bring the manholes to the under side, and then by means of rakes discharge the prepared fiber into barrows.

A modification of this apparatus is shown in the partial longitudinal section, Fig. 7, they object being to provide a central support for the cylindrical boiler-shell When the apparatus is made on a large scale. This support consists of a circular Skeleton-frame, P, which is made fast by bolts to the shell of the boiler, and is formed with a hub to fit the hollow axle and rotate smoothly thereon. This central stay or support will prevent the sagging of the boiler, the central aXle being of suitable f The passage of the fiber between these squeez- 1 ing-rollers Will not only discharge the Water contained therein, but will complete the separation of such fibers as may have been partially separated by the first crushing operation. r

The fiber thus prepared according' to our invention is now fit for conversion into paper. If it is desired to convert it into White paper, the fiber must be bleached in any well-known andapproved manner; butforinferior or coarse papers no bleaching` of the material Will be required.

From the foregoing description it will be nnderstood that the advantages of our improved mode of preparing fibers for paper-making are, first, that the fibers of the ground spent bark retain their normal length and are otherwise uninjured by the process; and, secondly, a valuable product consisting of tannic acid is for the first time obtained from the spent bark.

Having now set forth the nature of our nvention, we wish it to be understood that we claim The process of treating spent bark as above described, consisting in subjecting the same Vto the action of crnshing-rollers to reduce the knots to a fibrous state, and then submitting` the crushed material to agitation in a closed vessel under steam-pressure and in the presence of an alltaline solution, whereby the natural fibers of the barlt are separated and converted into half-stuff in an economical manner and the tannic acid contained in the spent bark is extracted in a concentrated form.

NVILLIAM GUEST. CHARLES COURT.

Witnesses: f H. K. WHITE, GEO. CANTLE,

G6 Ohanccry Lane, London.

IOO 

